Russian submarine collided with British warship part in rare event

The Royal Navy's HMS Northumberland is seen in a 2007 file photo.

(CNN)A Russian submarine being tracked by a British naval warship on patrol in the North Atlantic more than a year ago hit a sonar the ship was towing, according to the UK Ministry of Defence.

"In late 2020 a Russian submarine being tracked by HMS Northumberland came into contact with her towed array sonar," a UK Ministry of Defence spokesperson said in a statement Thursday.
"The Royal Navy regularly tracks foreign ships and submarines in order to ensure the defence of the United Kingdom," the statement said.
    A towed array sonar is a sensor spooled out by a ship when it is deployed.
      According to the British Royal Navy, the HMS Northumberland carried out a "vital mission to protect UK waters and the nation's nuclear deterrent" in 2020.